120 VENERID ZZ. 
P. pecussata, Linn. et nobis. 
Venus decussata, Auctorum. 
Tapes decussata, Brit. Moll. i. p. 379, pl. 25. f. 1. 
Animal thick, suboval, very pale creamy-white; mantle 
open, with the margins finely scalloped or dentated. Foot 
large, muscular, angulated, lanceolate, white, with a byssal 
groove. ‘Tubes subcylindrical, gently tapering, separate from 
their bases, of the same length, and, when extended, as long 
as the transverse measure of the shell; they are at times 
greatly inflated; the colour, to within a quarter of an inch of 
the orifices, is pale yellowish-white, interspersed with whiter 
minute flakes, and marked for about an inch at their termi- 
nations with confused yellowish-tawny or dark brown short 
lines or blotches; both the orifices are fringed, the branchial 
with about twelve long cirrhi with alternate smaller ones ; the 
anal has 16-20 of the same size, and generally both are of a 
bistre colour; the siphons, at the animal’s will, diverge in 
various directions. There are a pair of suboval branchiz on 
each side, the upper the smaller; they are more strongly 
pectinated on the inner than on their external areas, of a pale 
brown, aspersed with minute dark brown points. The palpi 
are very small for the size of the animal, triangular and 
striated as the branchial laminze. 
This species is much more common than the P. pullastra ; 
they live together in the same shingles, and have precisely the 
same habitudes; notwithstanding this community they are 
very distinct species. 
P. vircinea, Linn. et nobis. 
Tapes virginea, Brit. Moll. i. p. 388, pl. 25. f. 4, 6. 
aurea, Brit. Moll. 1. p. 392, pl. 25. f. 5. 
Venus Sarniensis, enea, nitens, Turt. et Auctorum. 
Animal inhabiting a suboval shell, furnished with close-set, 
blunt, rounded, stout, subconcentric striz; the ground colour 
is pale yellowish-white; the mantle is open throughout the 
ventral range, with its margins anteally dentated, medially 
sinuated, and posteally crenulated, with a few short yellow 
filaments at each extremity ; the animal emits anteriorly the 
